COASTAL RISKS, NATURE-BASED DEFENSES AND THE ECONOMICS OF ADAPTATION: AN APPLICATION IN THE GULF OF MEXICO, USA

Abstract

The need to reduce risks from coastal storms and climate change in coastal areas has given rise to efforts to make greater use of integrated ecosystem-based approaches. Assessment of the role and cost efficiency of adaptation measures is increasingly demanded. Applying the Economics of Climate Adaptation framework in the US Gulf Coast, we compare nature-based defenses, artificial defenses, and policy measures for adaptation and risk reduction and quantify their costs and benefits under a variety of economic growth and climate change scenarios. Our analyses are spatially explicit and all models, tools and information are open source. The framework includes (i) a probabilistic assessment of hazards, (ii) estimation of damages and (iii) assessment of adaptation and risk reduction measures. We perform sensitivity analyses to understand the parameters that created the most variation in risk assessment and most influenced estimates of cost effectiveness. We find that high rates of economic growth and coastal development are likely to create greater risks in the near term than climate change, due to the increase in exposed assets. Nature-based solutions such as oyster reef and marsh restoration are particularly cost effective, but their cost-effectiveness is highly dependent on where these measures are used. As decision-makers look for the most cost effective group of measures for adaptation and risk reduction, these approaches and results should be particularly useful for informing management priorities.